Since 1990, Hubble has made more than a million observations. We feature many of these on spacetelescope.org, and the most stunning are in our Top 100 gallery and iPad app.

But there are thousands of pictures in Hubble’s science archive that have only been seen by a few scientists. We call these images Hubble’s hidden treasures — stunning images of astronomical phenomena that have never been seen and enjoyed by the public.

Searching Hubble’s archive for hidden treasures is a lot of fun, and it’s pretty straightforward, even if you don’t have advanced knowledge. So we’re inviting you to come and help us find iconic Hubble images that have never before been shown to the public.

Hubble’s Hidden Treasures 2012: Find and tweak Hubble observations using a set of simple online tools. It’s easy and fun, and anyone can take part. Top prize: Apple iPod Touch and goodies.

Hubble’s Hidden Treasures 2012 Image Processing: Find Hubble observations and then process them using professional astronomical imaging software. An extra challenge for amateur astronomers or people keen to learn about astronomical image processing. Top prize: Apple iPad and goodies.

When you search the Hubble archive for hidden treasures, you’re playing with real data from the world’s most famous astronomical observatory. You’re helping to uncover stunning pictures for the whole world to enjoy. And you could be in with a chance of winning one of our great prizes.

We’ll publish a selection of the images you find and feature them in future photo releases and pictures of the week.